Concept explainers
(a)
The wavelengths that lies in the range of
(a)
Answer to Problem 15P
The wavelength that lie in the range of
Explanation of Solution
Write the expression for the Rydberg’s equation.
Here,
The number corresponding to the Paschen series of hydrogen spectrum is
Conclusion:
For Paschen series:
Substitute
Substitute
Substitute
Substitute
Substitute
Thus, the wavelength that lie in the range of
(b)
The reason for the visibility of the only three wavelengths by the detector.
(b)
Answer to Problem 15P
The three wavelengths are detected by the detector because the detector is moving away from the source and other wavelength is not visible for the detector.
Explanation of Solution
The wavelengths lying in the visible region are the four wavelengths that should be detected by the detector used. Since the detector is moving away from the source, there is a possibility that the higher wavelengths might have undergone red shift.
Due to red shift, the wavelength would have increased and might have gone out of the visible range of the
Conclusion:
Thus, the three wavelengths are detected by the detector because the detector is moving away from the source and other wavelength is not visible for the detector.
(c)
The speed of the stellar object that emits the spectrum.
(c)
Answer to Problem 15P
The speed of the moving stellar object is
Explanation of Solution
Write the expression for the relation between the observed wavelength and the wavelength from the source.
Simplify and rearrange the above expression for
Here,
Write the expression for the speed of the stellar object.
Here,
Conclusion:
Substitute
Substitute
Thus, the speed of the moving stellar object is
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Chapter 3 Solutions
MODERN PHYSICS F/SCI..-WEBASSIGN(MULTI)
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